(1) Field of the Invention
The present invention relates to a dynamic wrist-hand-finger orthosis or splint. In particular, the invention is well suited for the positioning and exercise of a neurologically impaired upper extremity, including the wrist, hand, and fingers.
(2) Description of the Prior Art
A dynamic wrist-hand-finger orthosis or splint is generally used for the positioning of an impaired, injured, or disabled wrist, hand, and fingers. Splints come in a variety of designs: static, static progressive, and dynamic that can be low profile or high profile.
U.S. Pat. Nos. 5,637,078 and 5,560,375 describe static rigid splints designed to hold the wrist, hand, and fingers in a static position. These splints are used following an injury, during surgery, and post surgery. They are generally made of aluminum with a cushion liner or plastic with a padded liner.
U.S. Pat. No. 4,945,902 describes a static progressive splint as one applying an infinitely adjustable progressive force to a finger, two adjacent fingers, or the thumb. A static progressive splint is designed to increase range of motion to shortened soft tissue.
U.S. Pat. No. 4,765,320 describes the use of a dynamic “low profile” splint to offer a tension force to the finger to overcome stiffness and immobility due to an injury or the hand being immobilized for a period of time. The patent also mentions that whenever possible the patient should be able to perform normal tasks with the splint in place.
U.S. Pat. No. 4,602,620 discloses a prefab splint outrigger system to be used in conjunction with a thermoplastic base. The disclosed system is for use on the postoperative hand for the precise alignment of dynamic splint forces following implant resection arthroplasty of the metacarpophalangeal joints.
All of the above-mentioned prior art and current splints are orthopedic in nature that either holds the hand in a static functional position, or uses a slight dynamic force to position the fingers. None of the known prior art is neurologically based and is designed to allow the user to exercise the impaired upper extremity including the wrist, hand, and fingers.
Many people suffering a neurological injury from stroke, cerebral palsy, brain injury, etc., often have upper extremity impairments. Many have some shoulder and elbow movements, but are unable to extend their wrist or fingers to grasp an object. This is usually due to hypertonicity, described in U.S. Pat. No. 5,807,293 as a condition where the flexor or extensor muscles in the upper extremities is spastic, and resists positioning.
Currently, dynamic splints offer slight resistance to hold a joint in a certain position. An effective dynamic splint designed to be used for hypertonicity must offer enough force to balance the effects of increased muscle tone (hypertonicity). Also current dynamic splints use a variety of finger cuffs to support the digits. These cuffs are not practical when working on a digit affected by hypertonicity, as they move proximal upon closing the fingers, and then have to be repositioned after opening the fingers manually.
Thus, there is a continuing need for a dynamic splint that will address these prior art deficiencies, and provide the user with an improved way to exercise an impaired upper extremity including the wrist, hand and fingers.